Apparatus for inflating and deflating gas main bags



Aug. 8, 1933. 1,922,003

APPARATUS FOR INFLATING AND DEFLATING GAS MAIN BAGS L. SHUMAN Filed June 12. 1931 MVEWfO/P WWW/z Patented Aug. 8, 1933 1:

APPARATUS FOR INFLATING AND DEFLAT- ING GAS MAIN BAGS Lawrence Shuman, Philadelphia, Pa., assignor to The United Gas Improvement Company, Philadelphia, Pa., a Corporation of Pennsylvania Application June 12, 1931. Serial No. 543,807

1 Claim.

The present invention relates to apparatus for stopping off the flow of gas in gas mains in order to be able to repair or remove a portion of the main.

It is usual practice in stopping off mains for this purpose to tap small holes on each side of the section to be repaired or removed and to insert inflatable bags through the holes, which when inflated stop the flow of gas on either side of the section and enable the work to be carried on without leakage.

The holes tapped in the main for the insertion of the bag are relatively small. The curvature of the main limits the size of the hole which will provide sufficient continuous thread to hold the threaded plug with which the hole must be afterwards closed in a gas tight manner.

After the work is completed the bag is deflated and withdrawn through the hole. It is very difficult in practice to deflate the bag sufficiently for removal through the small hole and there is frequently considerable delay in accomplishing it, during which time considerable quantities of gas may leak out through the hole. The

' delay causes loss of time and loss of gas and the leakage of gas is a source of danger.

The principal object of the present invention is to provide apparatus for the rapid and complete deflation of gas main bags so that they may be withdrawn from the main without delay, which may also be employed for their rapid and convenient inflation.

The invention will be described in connection with the attached figures which form a part of this specification and in which,

Figure 1 shows the apparatus in elevation connected for use.

Figure 2 shows a vertical cross section of a portion of the apparatus.

Referring to the figures:

1 generally indicates the gas main, 2 the section to be repaired or removed, 3 and 4 are gas main bags which have been inserted into the main on either side of section 2, while deflated, through holes 5 and 6 tapped into the main. 7 indicates a Y fitting having the branch 8, branch opening 9 and the run openings 10 and 11. Branch opening 9 is provided with bushing 12, nipple 13 and the female half of a union 14. The run opening 11 is provided with a nipple 15 open to atmosphere at 16 except when inflating a bag. The run opening 10 is provided with a pneumatic tool coupling 17, the fluid way of which discharges into the cone 18 which extends within the run of the Y fitting so that connected at 1'7 and the apparatus disconnected the discharge from the cone exerts an aspirating effect on the branch 8 when the nipple opening at 16 is not sufiiciently obstructed to cause pressure to build up in the branch. The bag, for instance bag 3, is provided with the stem 19: which is provided with nipple 20, cook 21 and nipple 22. Nipple 22 carries the male half of a union 23. i

To inflate a bag, for instance bag 3, as illustrated, coupling 17 is connected through line 2e with a source of air under pressure, for instance, an air compressor (not shown) and the union halves 14 and 23 are connected. The cook 21 is opened, air is turned on from the compressor. An operator, holds the palm of his hand over the outlet 19 as illustrated in Figure l, obstructing the outlet somewhat, causing pressure to build up in the branch 8 and air to flow back through the branch and into the bag in quantity sufficient to inflate the bag to the desired degree. The flow is indicated by the full arrows in Figure 2. When the bag is filled, the cook 21 is closed, the air is turned off from the source of supply and the source of supply dis- Whenthe bag is to be deflated, the source of air supply is again connected at 1'7. Union halves 14-23 are connected. The cock 21 is opened and the air supply turned on. The out let 16 is not obstructed and the discharge of air through the cone aspirates the air from the bag through branch 8 and deflates the bag in a few seconds, so that it may be easily and quickly removed from the main and the opening 5 closed; The flow on deflation is shown by the dotted arrows in Figure 2.

It will be obvious that a valve or cook may be placed on nipple 15 at 16 and operated to partially close the flow through the nipple during inflation of a bag, instead of the operator placing his hand over the end of the nipple.

I do not intend to be limited in the practice of my invention save as the scope of the priorglOO An apparatus for inflating and deflating gas main bags comprising in combination, means for compressing a fluid, a Y-fitting having run conical member and said branch opening, a bag adapted to be inflated and deflated in a gas pipe, a connection between said bag and said branch opening, and a valve controlling said last named connection. 7

LAWRENCE SHUMAN. 

